White letter problem

Dye cannot print white. White letter is a problem.

Basically, the only one way is printing every colors except for white. If the problem is just for top side, everything OK... Not in reality.

Printing on five sides

I yet haven't tried to print on five sides, but it seems hard. In the case of top side only, I run 6 batches for full-set keys. Better instruments can reduce the burden dramatically, of course, but the investment is huge. According to my speculation, around $3,000 for 1 batch process instruments at least. Larger keycap mount enables larger batch, but it requires better accuracy and durability which costs much. I cannot believe my DIY plaster jig works well at such region.

One batch time is around 15 minutes. 1.5 hours for 6 batches. Good. But 1.5x5=7.5 hours? Oh...

If printing on only one or few keys, red ESC key for example, the burden is not so hard. 1.25 hours for 20 pcs of red ESC key, Good.

But there is another obstacle.

Ridge line gap and overlap

Ridge line of keycap is not so sharp. Two cases are possible: gap and overlap.

Gap makes white line on ridge line. Very awkward. Overlap makes deep color line if the ink is not saturated. Therefore two principles are required:

1. Make overlap rather than gap.

2. Ink should be saturated.

Principle 1 means printing margin management. It requires some effort but makes no restriction.

Principle 2 means the restriction of the color. Saturated by unmixed single dye will be OK. But if mixed? Overlapping makes deeper color until all contained dyes saturate? I should test it before I print white letter...

If things go well, the restriction of the color isn't practical restriction. White letter on pale color is not practical. By the way, to print black letter on colored background, simply dye the keycap before printing.

Black key

About black, the problem is much easier. Black is perfectly saturated and color matching is easy. If light, make deeper, finish.

So I can use easier dyeing process for non-lettered sides. I mean, paint black dye by brush, heat, and wash off the dye. It is yet a burden, but 30 minutes for full-set keys, I suppose.